It is well-known that plastic parts cannot be manufactured though molding by one time due to its construction, and welding process may be used subsequently for fusion manufacturing. Commonly used welding processes include conventional hot plate welding, infrared welding, ultrasonic welding and vibration friction welding and so on, wherein ultrasonic welding and vibration friction welding are increasingly used for their excellent properties such as low consumption, self-orthopedic and smoke-free. Both ultrasonic welding and vibration friction welding are based on the basic principles of the generation of heat by friction, but vibration friction welding can be applied to larger area and larger volume (weight) of the plastic parts of the welding. No matter which kinds of the welding technology are used, the spillage after welding is inevitable. The spillage volume is directly proportional to the amount of welding. When the quantities of welding is large, it's necessary to deal with the spillage by means of either the design of spillage in the non-use area, or the subsequent processing removal, or the design of the material-blocking edge, spillage slot to improve the appearance of the spillage. For the parts whose welding structure cannot be designed in the non-use of the visible areas, spillage slot or subsequent processing removal are generally used to deal with the spillage when hit hot plate welding and infrared welding, and the material-blocking edge would be used to improve the appearance of the spillage when vibration friction welding is used. The amount of the welding is very limited when ultrasonic welding is used, so welding spillage is not discussed.
According to the welding result of our company actual products and other products on the site, the welding spillage of the vibration friction welding for the welding construction parallel to vibration direction differs from that perpendicular to vibration direction, and the difference is quite large. The welding spillage of welding ribs parallel to the vibration direction extends toward outside in the form of the sheet and has a wool-like outer end, and the degree of the spillage overflowing is larger, while the welding spillage of welding ribs perpendicular to the vibration direction is mostly in the form of extrusion paste and stick to welding ribs, and the degree of the spillage overflowing is small.
FIG. 1 is a schematic view of the welding design according to the general design guide of the welding block. As shown in FIG. 1, a component 100 and a component 200 are welded together by vibration friction welding and form a melt glue zone 202, wherein the component 200 is provided with a material-blocking edge 201. As illustrated in FIG. 1, the material-blocking edge 201 fails to completely seal a spillage zone 203, and therefore the material-blocking edge is generally able to confine the welding rib spillage perpendicular to the vibration direction but is unable to completely shield the welding rib spillage parallel to the vibration direction. In addition, the thickness of the material-blocking edge 201 is generally smaller.
In addition, for welding productions whose applicable environment is required to be hygienic, if material-blocking edge cannot be well aligned with the opposite side due to difference of molding size or failure for vibration welding mold to adjust in place, the cavity between the material-blocking edge and welding ribs will instead become a filthy place and hard to clean.